Subteeeanean line of electeic wiees



2 Sheets--Sheet I.

(N o Model.)

H. B. COBB.

SUBTEEEANEAN LINE 0E ELEGTEIG WIRES.

Patented Nov. 13, 1883.

N PETERS. Plmln-Lmmummven Mmmm. D.c.

No Model.) 2 Sheets-Sheet 2 H. B. COBB.

SUBTEREANEAN LINE 0E ELECTRIC WIRES.

No. 288,311. Patented Nov. 13, 1883.

UNITED STATES PATENT OFFICE.

HENRY B. COBB, OF VILMINGTON, DELAVARE.

SUBTERRANEAN LINE OF ELECTRIC WIRES.

SPECIFICATION forming part of Letters Patent No. 288,311, dated November13,1883.

Application tiled June 1,1883. (No model.)

To all whom it' 17mg/ concern.-

.Be it known that I, HENRY B. Conn, a citizen of the United States,residing at Vilmington, in the county of New Castle and State ofDelaware, have invented a new and Improved System of Laying SubterraneanLines of Elec tric Vii-es; and I hereby declare the following to be afull, clear, and exact description of the same.

My invention relates to the class of subterranean systems of electricconduiting-wires wherein the pernicious effects of induction areovercome by providing a metallic conduit to contain the insulated wiresfor the passage of electric currents, and by means of which, inconsequence of its immediate contact with the ground, the inductivecurrent is carried to earth.

The system recently patented by James T. Goodfellow has been found toanswer satisfactorily in overcoming the effects of the inductive currentwhen laid with care; but there is an almost insurmountable difficulty inthe matter ol' laying the insulated line-wire, which necessarily has itsinsulating medium formed of asoftsubstanee to permit of its being woundaround a reel, and is subject, even with the greatest care, to abrasionwhile it is being drawn through the conduit, thus exposing the wire.Besides, there are manifold details of mechanism which must be used inconnection with the system above refe rredto, whichfessentially make itintricate and unnecessarily eX- pensive.

It is my object to provide a system of laying subterranean lines ofelectric wires in which the difficulties referred to shall be entirelyovercome, and to this end my invention consists in providing a metallictube or series of metallic tubes within a metallic conduit, each with atube of an insulating substance inserted within it and inclosing theline-wire.

My invention consists, further, in certain details of construction andcombinations of parts, all as hereinafter more fully set forth.

In the drawings, Figure l is a plan view of my system, viewed in partthrough the opening leading to a man-hole, and showing by dottedlinesthe conduits lying under the ground along intersecting streets;Fig. 2, a central longitudinal section of the principal feature of myinvention, showing the manner of joining the sections of the outsidemetallic Itube and of the insulating-tube with the linewire in itsposition; Fig. 3, acentral longitudinal section of parts of two lengthsof the insulating-tube detached; Fig. 4, a transverse section of aconduit filled with metallic tubes containing the insulating-tubes andline-wires 5 Fig. 5, a longitudinal section of the same; Fig. 6, alongitudinal section of the device inside a man-hole, showing thearrangement provided to permit easy access to the different parts; andFig. 7, a perspective view of a detail.

A and A/ are metallic conduits, preferably of cylindrical form,(although they may be of any other form,) made in sections of anydesired length, to be connected together in the process of laying bymeans of suitable coupling-joints.

B is a man-hole located at the center of two intersecting streets. Asimilar man-hole may be provided wherever the streets intersect, and theconduit reaches from one such man-hole to another, but does not extendacross any of them. Each conduit is formed into a funnel shape at theends where it meets a man-hole, as shown at u.

To lay the wires by my system entrance is made into the man-hole, whenone section of the metallic tube C, which is always made of a lengththat will permit it to be handled with in the dimensions of the saidmanhole, is slipped into the conduit in the desired direc tion. Theoperator then takes another such tube and inserts the end thereof whichis tapered on its outer surface, as shown at c in Fig. 2, into that ofthe first named, which is made corresp ondinglytaperin g on its inn ersu rfaee near the end, as shown at t, to receive it, and slides themalong within the conduit suf- Iiiciently far to permit the performanceof a like operation with another length. As the ends of two lengths arethus connected by a slip-joint, they may, if desired, be cementedtogether. This operation may be continued until the desired length oftubing has been laid. rIhen follows the laying of the insulating-tube D.This tube is formed of an insulatin g substance-preferably, to secureproper hardness, of vulcanite-and, like the metallic tube, is made inlengths corresponding with those of the metallic tubes, but sufficientlysmaller in diameter to permit them to be passed y through the latter.The method of laying the `insulator is exactly the same as that oflaying the metallic tubes-.that is to say, of two lengths tapered on theouter surface toward one end, as shown at o', and on the inner surfacetoward the other, as shown at t, one is inserted into the other, whenthey are pushed along, and the operation repeated until the desiredlength has been laid. The line-wire isthen drawn through in the old way,if desired; but it is preferred, owing to the greater ease of itsaccomplishment, to push it through in the same direction that the tubesare passed through in laying them. Theliard quality of the insulatorwill prevent injury to it by friction against the wire, and the pushingcan readily be effected with a suitable contrivance, by means of whichthe wire is unwound from a reel in the man-hole and pushed betweenrollers, operated by a crank, along the interior of the insulator,whereby at the same time any kinks in the wire` are removed. Referenceto Figs. l and 6 of the drawings will show the arrangement of the tubeswithin the man-hole. As before stated, the conduit does not extendacross but terminates with a funnel-shaped extremity at the edge of theman-hole. The tubes containing the wires are made to extend into the.man-hole to a point two or more inches short of its center, a likedistanccbein g left on the other side of the said center, where thetubes are directed into the continuation of the conduit. The object ofdiscontinuing the conduit at its entrance to the man-hole, as described,is to permit ready access to any tube without disturbing the others, andto allow the different tubes to intersect each other within themanholes, and to be kept from contiguity with each ether, if desired,either by bending the tubes or by inserting suitable wedges betweenthem. rlhe arrangement of the tubes and wires within the man-hole, asindicated in Fig. l of the drawings, and clearly shown in Fig. 3, is topermit easy access to the wire whenever occasion demands without thenecessity of destroying or even injuring the metallic tube C or theinsulatingtube D. The following is a clear description of the saidarrangement: As hereinbefore stated, the metallic tube C andinsulating-tubes D extend into each manhole to a point near its center,and continue from a point equally distant 'on the other side of the saidcenter. A space suiiicient for the handling of the wire is thusprovided, and the latter can be laid in. sections extending'be-A tudinalsections held together to form a cylinder around the projections d bymeans of rings slipped over it and resting in notches formed around theexterior, near the ends thereof. It is not, however, deemed of greatimportance that the construction` of the sleeve Ev lshould be as justdescribed;` but it may be formed in one piece, when its destruction inseeking access to the wire will be inevitable, but of littleconsequence, owing to the slight expense necessary to replace it.

F is a metallic sleeve formed in two sections, y

and joined together around the projecting ends of the tubes C in theman-holes by means of rings r. This sleeve F is recessed on its innersurface sufficient to admit the sleeve E, which the system, the sleeve Fis removed by slipping' off the rings r, and thus separating its sec-`tions, when the sleeve E, if similarly formed, may be removed in thesame way, or broken away, if formed as shown in the drawings. Either ofthe three features-the metallic tube, the insulating-tube, or thewire-may be removed in any desired length on merely separating thesections of wire, and the removal can be accomplished without otherwisedisturbing any other than the part to be removed. The curved sections q(shown within the manhole) are intended to represent the manner ofchanging the course of any wire, with its surrounding tubes', from onestreet in either direction along an intersecting one. It is to permit`the gradual bend in the wire-containing tubes, by which4 they aredirected from one conduit, A, along an intersecting one, A,that theconduits are made flaring at their extremities where they meet theman-holes; and another reason is given in this connection fordiscontinuing ythe conduits at the man-holes viz., to permit theabove-described change of course of the tubes and wires. If any length,whether of the metallic or insulating tubing or wire, requires removal,it is only necessary to release it from its connections at two manholesbounding the intermediate required length, and, on disconnecting thewire, to draw it out. The metallic tubes C lie within the conduit,preferably in close contact with each other, in order that theinduction-current may pass unobstructed from them to the conduit, andthence to earth. Suitable T branches are provided along the conduit, topermit connection to-be made for electric-light or telephone wires withhouses. If desired, a conduit may be provided with' any number of tubesC at the time the said conduit is laid, whereby it will only benecessary to yinsert insulating-tubes and wires as they may be re- IIOquired, and these tubes may beAk of different sizes to accommodate wiresfor the various electrical purposes.

XVhat I claim as new, and desire to secure by Letters Patent, is-

l. In an underground system of electric conduetingwires, the combinationof the follow; ing elements, viz: a conduit of metal, one or moremetallic tubes, C, inclosed within the said conduit and in electricalcontact with it, and a tube, D, of insulating material, inserted througheach of the said tubes C, through the interiors of whichinsulating-tubes the separate wires are passed, substantially asdescribed.

2. In combination with the tube C, of metal, formed in short lengthscoupled together, the tube D, formed of an insulating substance in shortlengths coupled together and nclosed within the said tube C,substantially as described.

3. rIlhe combination of the metallic tube C, formed in lengths having atapered exterior at one end and a correspondingly-tapered in-.

terior at the other end, whereby they are connected together by aslip-joint, and the insulatingtubc D, inserted within the tube G, and

likewise formed in lengths having a tapered exterior at one end and acorrespondinglytapered interior at the other end, whereby the saidlengths are connected together by a slipjoint, substantially asdescribed.

4. vThe device for permitting aceessto electric conducting -wires withinthe man-hole, consisting of the combination of the following elements,viz: the insulating-tubes D, disconnected from each other, butprojecting beyond the metal tubes C, as shown at d, a sleeve, E, ofinsulating material, fitting over the projecting ends of the tube D, andthus connecting the same, a metallic sleeve, F, divided into two partslongitudinally, and tting over the ends of the tube C, thus connectingthe saine, and means for detachably holding the two parts of the sleeveF together, substantially as de scribed. v

HEXRY B. COBB.

In presence ot- Josnrn WAHL, WM. H., DYRENFORTH.

